Our path to the GRM UTCC:
Last weekend was the Grassroots Motorsports Ultimate Track Car Challenge at Buttonwillow Raceway Park in Central California. We were excited to get the invitation to participate and rearranged our race schedule to attend. We planned to take 3 weekends in a row to break-in the new Metrix Motorsport diff, work on setup, get additional seat time, practice the track, and show off a real grassroots effort. As is often the case, the racing gods had other plans.
T-minus 2 weeks found us a Willowsprings. We�d secured some free fuel, installed and broke in the new Metrix Motorsport diff, and worked down the punch list early� things were really going our way. First session of the day and as I�m gearing up to get in the car, Paul pulls in reporting it�s hot. Pegged the water at 250 hot. We did a lot of testing, received a few quick burns (�Yep, that�s hot�), pulled the valve cover and re-torqued the head trackside, but still overheating under boost. We�ve both read the book and seen the movie so we know how this ends� the head gasket did it.
Head back early and make plans to pull the head on Sunday, which goes fine. Monday is a holiday so no parts get ordered. Tuesday scramble to drop off the head and order parts via next day delivery. Wednesday night and Thursday night reassemble Friday pack up and drive to Buttonwillow.
T-minus 1 week at Buttonwillow: After an installation lap and visual inspection, Paul puts down one flying lap and comes in with temps a bit high (210) but within spec. Next session it�s obvious it�s getting hot but Paul is checking the gauge and catches things quickly. More tests and back into diagnosis mode, including the ECU data log. We start to look for other root causes including the water pump and radiator as it�s obvious we have a flow problem� half of the radiator hot and half cold. Back home on Saturday night.
� Sunday we pull the cooling system and plan our attack.
� Monday we flow test the radiator, order parts, and drop the spare head off at the machine shop. Monday night testing decision is to pull the head (again).
� Tuesday I tell my boss I�m taking Friday off. Tuesday night pull the head.
� Wednesday it�s back to the machine shop for input and analysis. The head checks out but we were getting blow-by between the compression chamber and the water jacket on the #4 exhaust side (again).
� Thursday � Jury duty and not feeling well� nothing gets done.
� Friday - GRM UTCC starts in 24 hours, the car is apart, and we don�t even have the parts to finish the job. We begin cleanup while waiting for parts to arrive. Head gasket arrives around 10:00 and the head is on by 1:00. We�re doing our best to be purposeful and careful. We tried to remove the pressure to work fast by putting a deadline of sunrise for completing the job. Take a break for lunch, parts and supplies. Pack the trailer, heat cycle and test the motor and finally get on the road just before 9:00pm.
T-minus 7 hours: Arrive Buttonwillow at midnight, go straight to bed.
GRM UTCC Day 1:
Now we arrive, unpack, tech. inspection, setup for practice, work down the check list and get Paul on track. Instead of 2 weekends of practice and tuning Paul gets to turn his first hot laps in 3 months.
We start leveraging the tools, and making setup changes but get only 2 practice sessions in before the enduro starts. The car is running great but after studying the ECU data log I get concerned about some knock. E-mail the files to Vic Sias who takes a look, cleans some cells up, and sends them right back but we won�t get to test before the morning. I believe this was the root failure we have been looking for over the past two weeks. Shame on me for not paying more attention to the ECU data log but the car has been running so well for so long that I took it for granted. I didn�t pay enough attention to the fact that we changed the fuel mix slightly, or that the weather was warmer than it had been, or that we had better boost control giving us more boost sooner.
We decide to watch the enduro race and finalize the livery. In addition to the required stickers from GRM, we felt it was important to get the full BMW CCA livery on the car in case we get some coverage in the magazine. What a relief to be able to relax, watch the race, walk the pit wall and not have to turn wrenches.
Between discussions with our tuner and post-race advice from the guys from Bullet, we made the smart call and decided to up the fuel grade to 110.
GRM UTCC Day 2:
Load the new ECU maps, up the octane with new fuel and get ready to run.
This is where it gets interesting� After looking at the wide array of cars and budgets it�s obvious that �home built� and �grassroots� means different things to different people, but like the self defining middle class, a lot of people decided that�s where they fit.
We�re starting to think we brought a knife to a gun fight, but we know we have a car built to a specific class and can�t expect to compete with an LS7 in a tube frame chassis under fiberglass or a supercharged S2000 powered Lotus 7. We never expected to see such awesome cars on track, and while we know we�re not in the hunt for top tier on the podium, we still want to make as strong a showing as possible. Then drivers start asking about driving multiple cars for different owners and it�s obvious we have some ringers. People are taking this very sseriously. It was totally cool!
Paul and I start strategizing and decide that it would not kill us to get a safety lap in from someone with more experience in BMW�s and at this track. It would also be nice to get some input on the car�s dynamics from a more experienced driver. remember, this is our first race car and build. It�s a tough decision to make, but Paul approaches the HPDE 1& 2 instructor, John Matthew, about laying down a hot lap in the car. John agrees, does one practice session with a student in the passenger seat, and we talk. He feels the brakes lack bite when you get on them hard, and that the rear end is a little sloppy. These were both issues Paul had with the car and we addressed the rear end by adding some bar back in. The brake issue was harder to pin down so John took it out for a timing session and laid down a 2:01.362 running 13CW. (6 seconds faster than Paul�s theoretical best, but he lacked the time to string all the segments together). John reported the rear was much better and that the brakes worked great at moderate speed, but he had to stand on them after running under boost. He was confident he could find at least another second when we get that fixed, but we didn�t have a spare booster (the likely culprit) with us, we let that time stand.
The racing gods repaid our hard work in unexpected ways. Although we didn�t turn in the fastest lap of the weekend, we quickly realized that was never in the cards. We did meet some great people, had a lot of fun, got to run on track with cars we might never have even seen, have the potential for some coverage in the magazine, and learned a few more things about race craft that will make us better the next time out. The Vorshlag guys were really nice guys who made a heck of a trip out from Dallas to be at the event. The staff from GRM were really nice to meet and a pleasure to speak with. NASA did a fantastic job both with the enduro (which we hope to run next year) and their coordination of the Grassroots Motorsport Ultimate Track Car Challenge.
A special thanks to our new sponsor, Metrix Motorsport whose differential allowed us to field a car as competitive as it could be.